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650 on a 500 frame

5526 Views 92 Replies 12 Participants Last post by  SirFoxx

Just wanted to start a general discussion about the thoughts, or personal experience of a cx/gl650 engine swapped onto a 500 frame. I've got a cx500 standard that I rip around every now and then, and I think the extra power from the 650 would be nice!

I've talked to murray about it several times, and I know he loves the extra power the 650 has to offer, even with the slightly longer gears.

What got me going on wanting to do this is, I picked up two GL650 engines from an estate sale for $100. One has the end of the camshaft snapped off, where the water impeller goes, and the other is complete. I need to stick my endoscope into the complete engine and see how the cylinders are, make sure the complete one is in decent shape and not blown up from lack of oil. Makes me curious why the PO was trying to take apart the other motor, and how hard he was prying at the impeller to break the cam.

I've been trying to get a 2nd starter as neither engine has one so I can also crank them over and listen for anything funny, but it seems they are becoming hard to come by and rather expensive. I'd use the one off my cx500, but I'd rather not drop the engine just to borrow a starter...

(if anyone has one they'd sell to me cheap I'd really appreciate it~)\

I think I have everything mentally written down that I am going to need / do for the swap:

Rae-San ignition, timing jumper to aggressive
12v coils
murray mid-pipes
rejet murray carbs
modify cx500 engine hangar
gl650 radiator + efan wiring
swap output shafts
inspect cam chain, replace mechanical seal while swapping output shaft
Swap over HD clutch springs?

I don't think I'm missing anything..but I probably am. If the cam chain tensioner isnt stretched to the max, I am going to leave it. No reason to change good parts. Same with the stator.

Only thing I have ordered right now is the 650 radiator, mainly because it was in great shape, came with the efan and the shroud for $70 shipped!

I may make a build thread once I get this project going. The hardest part will be modifying the engine hangar, but theres a video on youtube doing it, and its pretty easy if you have a welder (which i do lol).
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The 650 uses a taller impeller and pump cover.

I've not done this mod on a 650 and can't tell you which pieces you should be using but it will become obvious which bits you can use when you delve into it but I think you'll be using the 500 pump components.
The auto tensioners also break when left too long with a worn out chain and are virtually unobtainable.
A filtered catchcan/separator might just work...

You can buy suitable pod filters for the application.
You're likely right.

Murray has suggested a setup that places the end of the breather against the {carb} pod filter so that the engine will rebreathe the resulting fumes.

I prefer a proper breather separator.

My thingy uses one that has drains with caps that is drained at service per the factory item.

It's a labrynth type to maximise surface area for condensation to take place. Made from PVC pipe and capd.

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